Morphogenesis of T-tubules in heart cells: the role of junctophilin-2

The T-tubule (TT) system forms the structural basis for excitation-contraction coupling in heart and muscle cells. The morphogenesis of the TT system is a key step in the maturation of heart cells because it does not exist in neonatal cardiomyocytes. In the present study, we quantified the morphological changes in TTs during heart cell maturation and investigated the role of junctophilin-2 (JP2), a protein known to anchor the sarcoplasmic reticulum (SR) to TT, in changes to TT morphological parameters. Analysis of confocal images showed that the transverse elements of TTs increased, while longitudinal elements decreased during the maturation of TTs. Fourier transform analysis showed that the power of ~2 m spatial components increased with cardiomyocytes maturation. These changes were preceded by increased expression of JP2, and were reversed by JP2 knockdown. These findings indicate that JP2 is required for the morphogenesis of TTs during heart development.     

Protein array of Coxiella burnetii probed with Q fever sera

Coxiella burnetii is the etiological agent of Q fever.To identify its major seroreactive proteins,a subgenomic protein array was developed.A total of 101 assumed virulence-associated recombinant proteins of C.burnetii were probed with sera from mice experimentally infected with C.burnetii and sera from Q fever patients.Sixteen proteins were recognized as major seroreactive antigens by the mouse sera.Seven of these 16 proteins reacted positively with at least 45% of Q fever patient sera.Notably,HspB had the highest fluorescence intensity value and positive frequency of all the proteins on the array when probed with both Q fever patient sera and mouse sera.These results suggest that these seven major seroreactive proteins,particularly HspB,are potential serodiagnostic and subunit vaccine antigens of Q fever.     

Atomic force microscopy imaging of live mammalian cells

Atomic force microscopy (AFM) was used to examine the morphology of live mammalian adherent and suspended cells. Time-lapse AFM was used to record the locomotion dynamics of MCF-7 and Neuro-2a cells. When a MCF-7 cell retracted, many small sawtooth-like filopodia formed and reorganized, and the thickness of cellular lamellipodium increased as the retraction progressed. In elongated Neuro-2a cells, the cytoskeleton reorganized from an irregular to a parallel, linear morphology. Suspended mammalian cells were immobilized by method combining polydimethylsiloxane-fabricated wells with poly-L-lysine electrostatic adsorption. In this way, the morphology of a single live lymphoma cell was imaged by AFM. The experimental results can improve our understanding of cell locomotion and may lead to improved immobilization strategies.     

Secretory/releasing proteome-based identification of plasma biomarkers in HBV-associated hepatocellular carcinoma

For successful therapy, hepatocellular carcinoma (HCC) must be detected at an early stage. Herein, we used a proteomic approach to analyze the secretory/releasing proteome of HCC tissues to identify plasma biomarkers. Serum-free conditioned media (CM) were collected from primary cultures of cancerous tissues and surrounding noncancerous tissues. Proteomic analysis of the CM proteins permitted the identification of 1365 proteins. The enriched molecular functions and biological processes of the CM proteins, such as hydrolase activity and catabolic processes, were consistent with the liver being the most important metabolic organ. Moreover, 19% of the proteins were characterized as extracellular or membrane-bound. For validation, secretory proteins involved in transforming growth factor-β signaling pathways were validated in plasma samples. Alphafetoprotein (AFP), metalloproteinase (MMP)1, osteopontin (OPN), and pregnancy-specific beta-1-glycoprotein (PSG)9 were significantly increased in HCC patients. The overall performance of MMP1 and OPN in the diagnosis of HCC remained greater than that of AFP. In addition, this study represents the first report of MMP1 as a biomarker with a higher sensitivity and specificity than AFP. Thus, this study provides a valuable resource of the HCC secretome with the potential to investigate serological biomarkers. MMP1 and OPN could be used as novel biomarkers for the early detection of HCC and to improve the sensitivity of biomarkers compared with AFP.     

Soil microbial properties under different vegetation types on Mountain Han

This study investigated the influence of broadleaf and conifer vegetation on soil microbial communities in a distinct vertical distribution belt in Northeast China.Soil samples were taken at 0-5,5-10 and 10-20 cm depths from four vegetation types at different altitudes,which were characterized by poplar(Populus davidiana)(1250-1300 m),poplar(P.davidiana) mixed with birch(Betula platyphylla)(1370-1550 m),birch(B.platyphylla)(1550-1720 m),and larch(Larix principis-rupprechtii)(1840-1890 m).Microbial biomass and community structure were determined using the fumigation-extraction method and phospholipid fatty acid(PLFA) analysis,and soil fungal community level physiological profiles(CLPP) were characterized using Biolog FF Microplates.It was found that soil properties,especially soil organic carbon and water content,contributed significantly to the variations in soil microbes.With increasing soil depth,the soil microbial biomass,fungal biomass,and fungal catabolic ability diminished;however,the ratio of fungi to bacteria increased.The fungal ratio was higher under larch forests compared to that under poplar,birch,and their mixed forests,although the soil microbial biomass was lower.The direct contribution of vegetation types to the soil microbial community variation was 12%.If the indirect contribution through soil organic carbon was included,variations in the vegetation type had substantial influences on soil microbial composition and diversity.     

Newly discovered insect RNA viruses in China

Insects are a group of arthropods and the largest group of animals on Earth,with over one million species described to date.Like other life forms,insects suffer from viruses that cause disease and death.Viruses that are pathogenic to beneficial insects cause dramatic economic losses on agriculture.In contrast,viruses that are pathogenic to insect pests can be exploited as attractive biological control agents.All of these factors have led to an explosion in the amount of research into insect viruses in recent years,generating impressive quantities of information on the molecular and cellular biology of these viruses.Due to the wide variety of insect viruses,a better understanding of these viruses will expand our overall knowledge of their virology.Here,we review studies of several newly discovered RNA insect viruses in China.     

Radiolabeling and biodistribution of a nasopharyngeal carcinoma-targeting peptide identified by in vivo phage display

A dodecapeptide EDIKPKTSLAFR ligand targeting CEN- 1 human nasopharyngeal carcinoma （NPC） was identified by in vivo phage display. Two tridecapeptides and their derivatives, named YR13 （YEDIKPKTSLAFR）, EY 1 3 （EDIKPKTSLAFRY）, EY 1 3-NH2 （EDIKPKTSLAFRY-NH2） and Fmoc-YR 1 3 （Fmoc-YEDIKPKTSLAFR）, were synthesized and radiolabeled with ^[3]I. The stability in vitro, biodistribution and tissue distribution of selected phage particles in mice bearing NPC tumor were determined, and plasma metabolites analysis of radiolabeled peptides was carried out. Although Fmoc and NH2 groups could protect the peptide from deiodination, only Fmoc group inhibited the binding of Fmoc-YR13 to NPC tumors. The compound EY13-NH2, the C-terminal amide of peptide EY13, had the greatest serum stability, the least deiodination, and showed favorable tumor/blood ratios. The selected phage particles （phage 3 or phage 5） were more concentrated in NPC tumors than the control phage （initial phage display peptide library）. EY13 could also inhibit the binding of selected phage particles to tumors. The results indicated that EDIKPKTSLAFR was a good candidate in diagnostic and therapeutic NPC.     

Trehalose and trehalose-hydrolyzing enzyme in the haemolymph of Locusta migratoria infected with Metarhizium anisopliae strain CQMa102

Topical application of the Metarhizium anisopliae var. acridum specialist strain CQMa 102 to the locust Locusta migratoria manilensis results in changes of the concentrations of trehalose and glucose in the haemolymph. Micrographs of the locust haemolymph shows Metarhizium anisopliae can effectivly penetrate the external skeleton of locust and after 2 days infection, the hyphae body will appear in the haemolymph of infected insects. The time in decrease of trehalose concentration coincided with that in increase of trehalose-hydrolysing enzyme activity in the haemolymph of the fungus-infected insects. Overlay gel analysis indicated there was considerably more trehalose-hydrolysing activity in the haemolymph of locusts infected by fungus than in controls. A comparable isoform was identified in in vitro culture of the fungus, suggesting a fungal origin for the in vivo enzyme. Haemolymph trehalose decreased significantly during mycosis of locusts by M. anisopliae. All these results suggested that this fungus may take advantage of competing nutrient utilization against the insect by its trehalose-hydrolyzing enzyme secretion. It may provide fundamental knowledge for fungal pathogenesis.